The invention relates to a circuit current converter. More particularly, the invention relates to an intermediate voltage circuit current converter.
Current converters are used to convert electrical power with respect to voltage level, current level, frequency and phase angle. Current converters for the conversion of alternating voltage into direct voltage or from alternating current into direct current are referred to as rectifiers. In contrast, current converters for the conversion of direct voltage into alternating voltage or from direct current into alternating current are referred to as inverters. Current converters for the conversion of power, with voltages/currents, from one frequency into another frequency are referred to as frequency converters.
Current converters are specifically used to supply electrical energy to electrical machines and engines. As a result these electrical machines and engines can be controlled and regulated by the current converter. A further field of application is the control of energy flows, the compensation of harmonic waves and the provision of reactive power in power supply networks. Moreover current converters are involved in the low-loss transmission of energy by means of high voltage direct current (HVDC) transmission.
In order to reduce the harmonic components in the voltage and current on the AC side of the current converter, current converters with a higher number of phases are used. Compared with 2-point current converters, the output voltage of these current converters has a lower harmonic factor and allows for a higher intermediate voltage circuit and thus a higher output voltage on the alternating voltage side, with the same cut-off voltage. Three-point current converters therefore already have a wide field of application in different embodiments. Five-point current converters can achieve an even better output voltage quality.
Five-point current converters that are already known use very complex commutation circuits. The individual potentials, at least a large part of the individual potentials, must be connected to the power semiconductors in a low-inductance manner. This results in restrictions, due to the use of low-inductance bus bars or the spatial proximity of the individual components, for instance.